The present invention relates generally to down-the-hole drill (DHD) hammers. In particular, the present invention relates to a non-rotating drill bit for a down-the-hole drill hammer.
Typical DHDs include a hammer having a piston that is moved cyclically with high pressure gas (e.g., air). The piston generally has two end surfaces that are exposed to working air volumes (i.e., a return volume and a drive volume) that are filled and exhausted with each cycle of the piston. The return volume pushes the piston away from its impact point on a bit end of the hammer. The drive volume accelerates the piston toward its impact location on the back end of the drill bit. The overall result is a percussive drilling action.
Conventional drill bits 100, as shown in FIGS. 1 and 1A, used in DHD applications are typically constructed to include cutting inserts 102 that are positioned at a bottom end face of the drill bit. The cutting inserts 102 serve to cut rock or other material upon impact. However, due to the structure and spacing of the inserts 102, the drill bit must be rotated or indexed a certain amount after each cycle of the piston to reposition the cutting inserts upon a different region of a bore hole.
The need to rotate the drill bit in conventional DHD hammers imparts complexity in design of the DHD hammer as it necessitates a mechanism to rotate the drill bit. Increased complexity in DHD hammers consequently increases the likelihood that such hammers will fail during operational use, which occurs in very harsh environments over prolonged periods of time.
As such, a need exists for a DHD hammer than can address the foregoing needs of conventional DHD hammers. Such needs are satisfied by the DHD hammer of the present invention.